Control system for multi-beam free space optical endpoint

Patent metadata

Field	Value
Publication number	US-9438337-B2
Application number	US-201414292888-A
Country	US
Kind code	B2
Filing date	May 31, 2014
Priority date	May 31, 2014
Publication date	Sep 6, 2016
Grant date	Sep 6, 2016

Abstract

Free space optics (FSO) is a wireless technology that utilizes optical frequencies. Previously available FSO transceivers are restricted to point-to-point links because of the high directivity of laser light used to transmit data. By contrast, various implementations disclosed herein include a multi-beam FSO apparatus that is less reliant on point-to-point links, and includes a lens assembly and a planar array of optical communication devices. The lens assembly includes at least one surface shaped to direct ingress light received substantially within a first angular range towards a focal plane, and to direct egress light away from the focal plane into the first angular range. The planar array includes a plurality of optical communication devices arranged in association with the focal plane of the lens assembly, wherein each of the plurality of optical communication devices characterizes at least one of a plurality of optical communication link endpoints.

First claim

What is claimed is:

1. A method comprising:
at a multi-beam free-space optical device including optical communication devices, a lens assembly and channel control modules, wherein an active data channel is supported by a respective pairing of an optical communication device and a channel control module, wherein a first set of the optical communication devices is provided on a first substrate, and a second set of the optical communication devices is provided on a second substrate that is parallel to the first substrate, wherein the first substrate includes perforations that permit light beams to pass to and from the second set of optical communication devices on the second substrate, wherein the lens assembly includes a surface shaped to direct ingress light received substantially within a first angular range towards the optical communication devices, and to direct egress light away from the optical communication devices into the first angular range;
monitoring optical signal power received by one or more of the optical communication devices in order to detect an incoming optical data signal received using at least one of the optical communication devices;
assessing a detected incoming optical data signal in order to determine whether or not the incoming optical data signal corresponds to an active data channel; and
adjusting one or more pairings between the optical communication devices and the channel control modules in response to the assessment of the received optical signal.

2. The method of claim 1 , wherein monitoring optical signal power received by one or more of the optical communication devices comprises:
monitoring optical signal power received by a first one of the optical communication devices primarily supporting a first active data channel in combination with a first one of the channel control modules; and
monitoring optical signal power received by a second one of the optical communication devices, the second one of the optical communication devices being proximate to the first one of the optical communication devices.

3. The method of claim 2 , wherein the second one of the optical communication devices is adjacent to the first one of the optical communication devices.

4. The method of claim 2 , wherein the second one of the optical communication devices is not primarily supporting the first active data channel while the first one of the optical communication devices is primarily supporting the first active data channel.

5. The method of claim 1 , wherein a first active data channel is primarily supported by a first one of the optical communication devices in combination with a first one of the channel control modules, and assessing further comprises:
determining whether the optical signal power received by a second one of the optical communication devices satisfies a criterion relative to the optical signal power received by the first one of the optical communication devices.

6. The method of claim 5 , wherein the criterion includes at least one of:
whether the optical signal power received by the second one of the optical communication devices is greater than the optical signal power received by the first one of the optical communication devices;
whether a bit error rate of the optical signal received by the second one of the optical communication devices is less than a bit error rate of the optical signal received by the first one of the optical communication devices; and
whether the optical signal power received by the second one of the optical communication devices is rising relative to the optical signal power received by the first one of the optical communication devices.

7. The method of claim 1 , wherein a first active data channel is primarily supported by a first one of the optical communication devices in combination with a first one of the channel control modules, and adjusting one or more pairings further comprises:
transferring primary support of the first active data channel to a combination of a second one of the optical communication devices and the first one of the channel control modules, in response to a change in the received optical signal power.

8. The method of claim 7 , wherein transferring primary support of the first active data channel comprises adding the second one of the optical communication devices to a multicast group associated with the first active channel.

9. The method of claim 7 , wherein transferring primary support of the first active data channel comprises:
transmitting a communication pause instruction on the first active channel;
determining whether or not an ingress data flow on the first active channel has paused; and
disconnecting the first optical communication device from the first channel control module, in response to determining that the data flow has paused.

10. The method of claim 9 further comprising:
pairing the second optical communication device with the first channel control module;
transmitting a resume communication instruction on the first active channel;
determining whether the data flow has resumed using the second optical communication device; and
removing the first optical communication device from a multicast group associated with the first active channel and returning it to a free pool for reuse.

11. The method of claim 1 , further comprising:
transmitting an acquisition beacon signal using a first one of the optical communication devices that are not currently supporting respective active data channels; and
determining whether or not an acknowledgment is received in response to the transmission of the acquisition beacon signal, wherein adjusting one or more pairings includes establishing a new pairing between the first one of the optical communication devices and a first one of the channel control modules that are not currently supporting respective active data channels, the new pairing supportive of a new active data channel.

12. The method of claim 11 , wherein establishing the new pairing includes coupling the first one of the optical communication devices and the first one of the channel control modules through a cross-bar switch.

13. The method of claim 11 , wherein monitoring optical signal power comprises monitoring optical signal power received by the first one of the optical communication devices for a limited duration, after which it is deemed that a valid acknowledgement will not be received in response to the transmission of the acquisition beacon signal.

14. The method of claim 1 , wherein:
monitoring optical signal power comprises monitoring a first one of the optical communication devices that are not currently supporting respective active data channels, assessing a detected incoming signal in order to determine whether or not an acquisition beacon signal is being received by the first one of the optical communication devices, and adjusting one or more pairings includes establishing a new pairing between the first one of the optical communication devices and a first one of the channel control modules that are not currently supporting respective active data channels.

15. The method of claim 14 further comprising transmitting an acknowledgment using the first one of the optical communication devices.

16. The method of claim 14 , wherein establishing the new pairing includes coupling the first one of the optical communication devices and the first one of the channel control modules through a cross-bar switch.

17. An apparatus comprising:
a plurality of free-space optical communication devices;
a lens assembly including a surface shaped to direct ingress

Assignees

• Cisco Tech Inc
• Cisco Tech Inc

Inventors

• Byers Charles Calvin

Classifications

• H04B10/11 Primary

  Arrangements specific to free-space transmission, i.e. transmission through air or vacuum · CPC title

• H04B10/07955

  Monitoring or measuring power · CPC title

• H04B10/1123 Primary

  Bidirectional transmission · CPC title

• H04B10/1143

  Bidirectional transmission · CPC title